1. Field of the Invention
The invention relates to a method and an apparatus for laterally aligning a sheet in a processing machine, in particular a printing machine. The invention also relates to a sheet-fed printing machine having the apparatus.
It is known for the entire cylinder to be displaced for the lateral alignment of a sheet on a cylinder.
An alternative possibility is disclosed in European Patent EP 1 334 829 B1, in which only one sheet-gripping gripper device of a sheet-guiding cylinder is displaced. That gripper device has an actuating drive, which is disposed in a stationary manner in an extension of the cylinder axis, and a stationary actuating gear mechanism, which acts on the gripper bar through a driver and an axially disposed pulling rail, which rotates synchronously with the cylinder. A device providing for rotary disengagement between the actuating gear mechanism and pulling rail is disposed outside the cylinder.
European Patent EP 1 354 833 B1 discloses a method of prepositioning a gripper device on a cylinder of a printing machine in which, due to a sheet position being measured through the use of a sensor, the gripper device is displaced in each case by half the position-correction value in the opposite direction, corresponding to the correction, prior to the sheet being gripped. Once the sheet has been gripped, the gripper device is then displaced by the total correction value.